A wireless communication system broadcasts so-called system information to wireless communication devices in order to assist those devices with operating in the system. System information may include, for example, parameters that describe general information about the system, including the Public Land Mobile Network (PLMN) ID, the system bandwidth, and the like. System information may also include parameters that describe information specific to certain cells in the system, such as the allocation of control channels, paging channel information, cell selection information, and so on.
System information may change from time to time. Known approaches effectively inform devices about such a change by embedding a value tag in the block or message that includes system information. A device reads the block or message in order to check the value tag. If the value tag has changed, the device considers the system information in the block or message to have changed and continues on with reading the system information in the block or message. If the value tag has not changed, the device only reads the system information in the block or message if at least a predefined validity time has passed since the device last read the system information from the block or message.
Known approaches, however, inherently impose limitations on how often the system information may be changed and still be read by a wireless communication device. This may prove problematic in some contexts where system information changes frequently. Adding more value tags would allow more frequent system information changes, but would unacceptably increase signalling overhead.